Rotary valve for automatic transmission.

摘要

An oil passage (120) is provided in an axially central portion of a spool (7) which is received within a valve housing (1) and rotatively driven by a pulse motor (6), and oil passages (121-125) passed diametrically through the spool (7) and connected to said oil passage (120), so that a hydraulic pressure from an input port (13) connected to a hydraulic pressure source (S) is selectively supplied to the oil passages (121-125) for selectively engaging and disengaging frictionally engaging elements of an automatic transmission. An axially acting load provided by the hydraulic pressure is received by a thrust bearing (10) mounted at an end of the spool (7). The supply of oil from the axial portion of the spool enables no side force to be applied, thereby reducing the frictional force and to enhance the sealability between the valve housing (1) and the spool (7).